From c76c0f017fa884c4b9a04ff7fa3b43d331c82d84 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Tue, 23 Feb 2010 14:21:48 -0500
Subject: Determine nthreads in dmnsn_new_scene().

---
 dimension/main.c        | 26 ++++++++++++++------------
 libdimension/raytrace.c | 15 +++++----------
 libdimension/scene.c    |  8 +++++++-
 3 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/dimension/main.c b/dimension/main.c
index 00c0fdf..fa7f5a6 100644
--- a/dimension/main.c
+++ b/dimension/main.c
@@ -39,18 +39,18 @@ main(int argc, char **argv) {
 
   /* Long-only option codes */
   enum {
-    DMNSN_NTHREADS = 256
+    DMNSN_OPT_THREADS = 256
   };
 
   static struct option long_options[] = {
-    { "output",   required_argument, NULL,      'o'            },
-    { "input",    required_argument, NULL,      'i'            },
-    { "width",    required_argument, NULL,      'w'            },
-    { "height",   required_argument, NULL,      'h'            },
-    { "threads",  required_argument, NULL,      DMNSN_NTHREADS },
-    { "tokenize", no_argument,       &tokenize, 1              },
-    { "parse",    no_argument,       &parse,    1              },
-    { 0,          0,                 0,         0              }
+    { "output",   required_argument, NULL,      'o'               },
+    { "input",    required_argument, NULL,      'i'               },
+    { "width",    required_argument, NULL,      'w'               },
+    { "height",   required_argument, NULL,      'h'               },
+    { "threads",  required_argument, NULL,      DMNSN_OPT_THREADS },
+    { "tokenize", no_argument,       &tokenize, 1                 },
+    { "parse",    no_argument,       &parse,    1                 },
+    { 0,          0,                 0,         0                 }
   };
 
   int opt, opt_index;
@@ -105,12 +105,12 @@ main(int argc, char **argv) {
         break;
       }
 
-    case DMNSN_NTHREADS:
+    case DMNSN_OPT_THREADS:
       {
         char *endptr;
         nthreads = strtoul(optarg, &endptr, 10);
         if (*endptr != '\0' || endptr == optarg) {
-          fprintf(stderr, "Invalid argument to --nthreads!\n");
+          fprintf(stderr, "Invalid argument to --threads!\n");
           return EXIT_FAILURE;
         }
         break;
@@ -216,7 +216,9 @@ main(int argc, char **argv) {
     return EXIT_FAILURE;
   }
 
-  scene->nthreads = nthreads;
+  /* Set the new number of threads if --threads changed it */
+  if (nthreads)
+    scene->nthreads = nthreads;
 
   /*
    * Now we render the scene
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index 6721a9b..3fa873c 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -19,7 +19,6 @@
  *************************************************************************/
 
 #include "dimension_impl.h"
-#include <unistd.h> /* For sysconf */
 
 /*
  * Boilerplate for multithreading
@@ -109,20 +108,16 @@ static void *dmnsn_raytrace_scene_multithread_thread(void *ptr);
 static int
 dmnsn_raytrace_scene_multithread(dmnsn_raytrace_payload *payload)
 {
-  int i, j, nthreads = payload->scene->nthreads;
+  int i, j;
   void *ptr;
   int retval = 0;
   dmnsn_raytrace_payload *payloads;
   pthread_t *threads;
 
-  if (!nthreads) {
-    /* Find the number of processors/cores running (TODO: do this portably) */
-    nthreads = sysconf(_SC_NPROCESSORS_ONLN);
-    if (nthreads < 1) {
-      nthreads = 1;
-    }
-    /* End non-portable section */
-  }
+  unsigned int nthreads = payload->scene->nthreads;
+  /* Sanity check */
+  if (nthreads < 1)
+    nthreads = 1;
 
   payloads = malloc(nthreads*sizeof(dmnsn_raytrace_payload));
   if (!payloads) {
diff --git a/libdimension/scene.c b/libdimension/scene.c
index 8973005..8ebf706 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -20,6 +20,7 @@
 
 #include "dimension.h"
 #include <stdlib.h> /* For malloc */
+#include <unistd.h> /* For sysconf */
 
 /* Allocate an empty scene */
 dmnsn_scene *
@@ -39,7 +40,12 @@ dmnsn_new_scene()
     scene->lights   = dmnsn_new_array(sizeof(dmnsn_light *));
     scene->quality  = DMNSN_RENDER_FULL;
     scene->reclimit = 5;
-    scene->nthreads = 0;
+
+    /* Find the number of processors/cores running (TODO: do this portably) */
+    int nprocs = sysconf(_SC_NPROCESSORS_ONLN);
+    if (nprocs < 1)
+      nprocs = 1;
+    scene->nthreads = nprocs;
   }
   return scene;
 }
-- 
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